Answer:
Step-by-step explanation:
Using the rule of exponents
= , then
=
Answer: a
Step-by-step explanation:
Answer:
7 years
Step-by-step explanation:
Given that:
Let Richard's age = x
Elder sister's age = 2x
Youngwr sister's age = x - 2
Product of sisters ages = 70
2x * (x - 2) = 70
2x² - 4x = 70
2x² - 4x - 70 = 0
x² - 2x - 35 = 0
x² - 7x + 5x - 35 = 0
x(x - 7) +5(x - 7) = 0
(x - 7) or (x + 5) = 0
x = 7 or x = - 5
X can't be negative
Hence, x = 7
Richard is 7 years
The total surface area of the triangular prism that has a height of h and the side length of a is given below.
<h3>What is a triangular prism?</h3>
A triangular prism is a closed solid that has two parallel triangular bases connected by a rectangle surface.
A box is in the shape of an equilateral triangular prism.
If the box is to be covered with paper on its lateral sides.
Let a be the side length of the equilateral triangle and h be the height of the prism.
Then the surface area of the triangular prism will be
Surface area = 2 × area of triangle + 3 × area of the rectangle
The area of the triangle will be
The area of the rectangle will be
Then the total surface area will be
More about the triangular prism link is given below.
brainly.com/question/21308574
Answer:
2.28% of tests has scores over 90.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation , the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
What proportion of tests has scores over 90?
This proportion is 1 subtracted by the pvalue of Z when X = 90. So
has a pvalue of 0.9772.
So 1-0.9772 = 0.0228 = 2.28% of tests has scores over 90.